Would you change your gears

Discussion in 'Tires | Wheels' started by mario, Feb 17, 2008.

  1. mario

    mario Active Member

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    I have an o5 dodge diesel dually w/an automatic and 3.73's I've had the tranny repaired 4 times and replaced once by the dealer:mad: . The truck is still under warranty so trans upgrades are out, but i'm friends with the service writer and we spoke about maybe jumping up to 4.10's or .11's:stir: to take some stress off the trans when i'm real heavy, if you look at my pictures you'll see i tow real heavy. He say's his tech's will never know. I'd have to do both axles and i don't really know if it's gonna be real beneficial. Any ideas or info would be helpful, i'd even consider some type of 5 or 6 speed auto tranny swap at this point to get a lower 1st and 2nd gear. Any info on that would also be greatly appreciated. Thanks in advance
     
    Last edited: Feb 17, 2008
  2. Rob Knoell

    Rob Knoell Well-Known Member

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    4.10 or 4.11 gears would help, however, I am unsure as to how much it would help. Tranny upgrades would also help but, I understand that you are still within warranty. How much more time or mileage till you are out of the warranty? Maybe just an extra tranny cooler would help. If I understand correctly the auto tranny is killed by heat. Perhaps it would also help. If you are willing to do a tranny swap you may also want to look at replacing your auto with a standard and a South Bend clutch. Just my .02.

    LT.
     
  3. mario

    mario Active Member

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    I put a much larger trans cooler but didn't make much of a difference, I also thought of a manual swap, but all i did was think about it. I spend all day fixing s@#$ and fabbing stuff for other people that i just want something that swaps right in and is reliable. I guess a manuel is the way to go but i'll really miss my auto in nyc traffic.
     
  4. Rob Knoell

    Rob Knoell Well-Known Member

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    The only other thing that I could think of that would not cause you to have to fix anything or fab up anything is to trade off your truck and get a bigger one. Perhaps a 5500 cab and chassis, from Dodge of corse, or maybe even a freightliner sport chassis. I know that it sucks getting rid of a vehicle that you have poured your heart and soul into but, without doing all the work of swapping in a new tranny and hoping that it would work better this may be your best bet. Hope this helps.

    LT.
     
  5. RJF's Red Cummins

    RJF's Red Cummins TRC Staff Moderator

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    1. No, I don't think 4.10's will help much at all. The only real difference where it could help is if you are constantly taking off from a dead stop loaded, like in city traffic or something. That is when the converter builds the most heat.

    2. If you are just totally overloading the truck, then a trans swap or gear change isn't going to fix a truck that is too small for the job.
     
  6. strictlyv8

    strictlyv8 Well-Known Member

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    You could also look into a gear splitter as well. But a built tranny should do the trick.
     
  7. mario

    mario Active Member

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    Do any of you guys know of anyone who makes a splitter, gear vendors is only an overdrive not an underdrive
     
  8. Rob Knoell

    Rob Knoell Well-Known Member

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    Klune V I think is the company that makes the under drive. I know that they make some for the purpose of four wheeling. I am not too sure about this product for towing applications.

    LT.
     
  9. Woods

    Woods Well-Known Member

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    If the trans is in good shape right now. I would put a good valve body and torque converter in it ASAP. Gears would help a little, but not as much as a an aftermarket VB/TC. Otherwise, time for a medium duty truck or one with a manual trans.
     
  10. SoCal98TwelveValveAuto4x4

    SoCal98TwelveValveAuto4x4 Well-Known Member

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    I have 4.10s in my truck with an NV4500 and 37" tires. It's geared too low for the speeds I run on the California freeways, engine runs too fast for good mileage.
     
  11. Seventy4Blazer

    Seventy4Blazer Well-Known Member

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    im gonna vote for a medium duty with a manual... lol

    you could try it, but why not see if they will help with the costs?

    it will cut your towing speed down to about 60-65 if you want to keep MPG on the flats, but it will help with the hill MPG.
     
  12. SoCal98TwelveValveAuto4x4

    SoCal98TwelveValveAuto4x4 Well-Known Member

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    What's the ideal RPM for the Cummins on the flat?
     
  13. luckyhat12

    luckyhat12 Active Member

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    I have read 1800-2000. I hauled my trailer (25k gross) at 2k RPM and saw a 2-3mpg increase over running at 2200.
     
  14. SoCal98TwelveValveAuto4x4

    SoCal98TwelveValveAuto4x4 Well-Known Member

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    Proly gain more running unloaded, no?
     
  15. LOUDandPROUD

    LOUDandPROUD Well-Known Member

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    I would guess that the best RPM to run on the flat would be the lowest, it makes peak torque at 1600 but you would have to do some gear work in order to cruise that low. But there again, the lower and slower you run will probably always net better economy...
     
  16. 67Cowboy

    67Cowboy New Member

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    Geared for Success

    I'm new here, been reading and enjoying the threads on this site. I found you guys during a quest for information in my own research. First I want to say that I think we are all BLESSED to have the awesome trucks we have and I would love to have had these kinds of trucks thirty years ago when I was hauling 10-20,000 pounds with a 250cid 6cylinder with a manual three speed shift on the column transmission. Running such a light weight rig taught me to take my time and use the momentum rather than let it work against me.
    _ That being said, Since Dodge has fixed the transmission at hand 4 times already, my question would be which part failed and why: Improper installation ? Poor Design ? Over exertion ? Knowing that answer would tell me what to do next Warranty or not. If I have this kind of money invested in my truck I'm not going to keep (ie the 5th time) taking it back to the same shop because sooner or later something bigger is going to break and dealerships have a way of blaming you for the problem so they can charge you for their high dollar work and poor parts.
    _ Gear Venders does have an over/under drive I'll try and post a photo below, also there is the Ranger*, Spicer #5381(Browny), Atlas, and what I'm working on now NP203/205 Doubler. http://www.high-impact.net/transmission_and_gear/doubler.htm


    Also there is a lot of new technology in the automatic transmission industry as of late take a look at http://www.dieseltrans.com/index.htm
    I would also spend some time calculating my Engine RPM(power band) and axle RPM try this, http://www.accuautoparts.com/calculatorfin.jsp

    What you find is too many RPMs over work the engine and tranny and not enough rpms means too tall/ high a gear ratio. What some guys don't realize is changing from 31" tall tires to 35" tall tires is like going from 4.10 to 1 ratio to 3.438 to 1 ratio, so tire size is a factor. You need to figure out what your average speed is and then calculate your engine and axle rpm then you will know what you are over working and where you can change gearing to alleviate your problems.;)
     

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  17. 4054x4

    4054x4 Well-Known Member

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    I would say that going to 4.10s would help marginally if all you do is tow heavy in city traffic. But RJF is right, if you are overloading your truck the only real fix is to get a truck that is big enough for the job; ie. f-550 or something.
     

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